Effects of Saccharomyces cerevisiae fermentation products on performance and rumen fermentation and microbiota in dairy cows fed a diet containing low quality forage

Abstract

BackgroundA possible option to meet the increased demand of forage for dairy industry is to use the agricultural by-products, such as corn stover. However, nutritional value of crop residues is low and we have been seeking technologies to improve the value. A feeding trial was performed to evaluate the effects of four levels of Saccharomyces cerevisiae fermentation product (SCFP; Original XP; Diamond V) on lactation performance and rumen fermentation in mid-lactation Holstein dairy cows fed a diet containing low-quality forage. Eighty dairy cows were randomly assigned into one of four treatments: basal diet supplemented with 0, 60, 120, or 180 g/d of SCFP per head mixed with 180, 120, 60, or 0 g of corn meal, respectively. The experiment lasted for 10 wks, with the first 2 weeks for adaptation.ResultsDry matter intake was found to be similar (P > 0.05) among the treatments. There was an increasing trend in milk production (linear, P ≤ 0.10) with the increasing level of SCFP supplementation, with no effects on contents of milk components (P > 0.05). Supplementation of SCFP linearly increased (P < 0.05) the N conversion, without affecting rumen pH and ammonia-N (P > 0.05). Increasing level of SCFP linearly increased (P < 0.05) concentrations of ruminal total volatile fatty acids, acetate, propionate, and butyrate, with no difference in molar proportion of individual acids (P > 0.05). The population of fungi and certain cellulolytic bacteria (Ruminococcus albus, R. flavefaciens and Fibrobacter succinogenes) increased linearly (P < 0.05) but those of lactate-utilizing (Selenomonas ruminantium and Megasphaera elsdenii) and lactate-producing bacteria (Streptococcus bovis) decreased linearly (P ≤ 0.01) with increasing level of SCFP. The urinary purine derivatives increased linearly (P < 0.05) in response to SCFP supplementation, indicating that SCFP supplementation may benefit for microbial protein synthesis in the rumen.ConclusionsThe SCFP supplementation was effective in maintaining milk persistency of mid-lactation cows receiving diets containing low-quality forage. The beneficial effect of SCFP could be attributed to improved rumen function; 1) microbial population shift toward greater rumen fermentation efficiency indicated by higher rumen fungi and cellulolytic bacteria and lower lactate producing bacteria, and 2) rumen microbial fermentation toward greater supply of energy and protein indicated by greater ruminal VFA concentration and increased N conversion. Effects of SCFP were dose-depended and greater effects being observed with higher levels of supplementation and the effect was more noticeable during the high THI environment.

Dynamic role of single‐celled fungi in ruminal microbial ecology and activities

“…Anaerobic fungi are among the most active organisms in fibre digestion in the known biological world, mainly due to their efficient and extensive types of enzymes for the degradation of structural polymers of plants (Solomon et al ). Supplementation of S. cerevisiae fermentation product increased the rumen fungi population (Zhu et al ), and similar results were reported in a previous in vitro study (Mao et al ).…”

“…The inclusion of S. cerevisiae at dose of 5 g per day per head in early lactating cows increased rumen pH, fibrolytic and lactate‐utilizing bacteria (Pinloche et al ). Zhu et al () reported that rumen microbial population was altered in response to S. cerevisiae supplementation. Supplementation with S. cerevisiae could provide various growth factors, provitamins, and/or micronutrients that help stimulate the growth of ruminal bacteria (Newbold et al ; Fig.…”

“…However, ruminal protozoa vary substantially in its contribution to plant degradation and methane production. The population of protozoa in the rumen fluctuates with changes in the diet consumed by the animal, a reduction in the number of protozoa in response to S. cerevisiae fermentation product may reduce bacteria engulfing with concomitant increase in microbial protein supply to the small intestine (Zhu et al ). The contribution of protozoa in the fermentation of nutrients in the rumen remains controversial.…”

“…In vivo and in vitro studies have documented positive effects of S. cerevisiae fermentation products on rumen fermentation (Mao et al ). Increases in rumen propionic acid concentration was observed when S. cerevisiae fermentation products was fed (Zhu et al ) that would lead to increased glucogenic potential of the diet and milk production. Monnerat et al () observed that 1 g of S. cerevisiae increased total VFA in cattle fed high concentrate diet of two starch levels.…”

“…Moya et al () reported that addition of live yeast increased efficiency of microbial protein synthesis in a continuous culture system. The decrease in number of protozoa in response to S. cerevisiae fermentation product supplementation may decrease bacterial preying and allows more microbial protein to reach the small intestine (Zhu et al ). Such effects have been reported in some other studies (Mao et al ).…”